Abstract: A computer program product for mitigating conflicts for shared cache lines between an owning core currently owning a cache line and a requestor core. The computer program product includes a tangible storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method. The method includes determining whether the owning core is operating in a transactional or non-transactional mode and setting a hardware-based reject threshold at a first or second value with the owning core determined to be operating in the transactional or non-transactional mode, respectively. The method further includes taking first or second actions to encourage cache line sharing between the owning core and the requestor core in response to a number of rejections of requests by the requestor core reaching the reject threshold set at the first or second value, respectively.

Abstract: A computer program product for mitigating conflicts for shared cache lines between an owning core currently owning a cache line and a requestor core. The computer program product includes a tangible storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method. The method includes determining whether the owning core is operating in a transactional or non-transactional mode and setting a hardware-based reject threshold at a first or second value with the owning core determined to be operating in the transactional or non-transactional mode, respectively. The method further includes taking first or second actions to encourage cache line sharing between the owning core and the requestor core in response to a number of rejections of requests by the requestor core reaching the reject threshold set at the first or second value, respectively.

Abstract: According to an embodiment, a computer system for cache management includes a processor and a cache, the computer system configured to perform a method including receiving a first store request for a first address in the cache and receiving a first fetch request for the first address in the cache. The method also includes executing the first store request and the first fetch request, latching the first store request in a store write-back pipeline in the cache, detecting, in the processor, a conflict following execution of the first store request and the first fetch request and receiving the first store request from a recycle path including the store write-back pipeline and executing the first store request a second time.

Abstract: Responsive to receiving a logical address for a cache access, a mechanism looks up a first portion of the logical address in a local cache directory for a local cache. The local cache directory returns a set identifier for each set in the local cache directory. Each set identifier indicates a set within a higher level cache directory. The mechanism looks up a second portion of the logical address in the higher level cache directory and compares each absolute address value received from the higher level cache directory to an absolute address received from a translation look-aside buffer to generate a higher level cache hit signal. The mechanism compares the higher level cache hit signal to each set identifier to generate a local cache hit signal and responsive to the local cache hit signal indicating a local cache hit, accesses the local cache based on the local cache hit signal.

Abstract: Provided are techniques for handling a store buffer in conjunction with a processor, the store buffer comprising a free list; a merge window; and an evict list; and logic, for, upon receipt of a T_STORE operation, comparing a first address associated with the T_STORE operation with a plurality of addresses associated with previous T_STORE operations, wherein the previous T_STORE operations are part of the same transaction as the T_STORE operation and the entries corresponding to the previous T_STORE operations are stored in the merge window; in response to a match between the first address and a second address, associated with a second T_STORE operation, of the plurality of addresses, merging a first entry corresponding to the first T_STORE operation with a second entry corresponding to the second T_STORE operation; and consolidating results associated with the first T_STORE operation with results associated with the second T_STORE operation.

Abstract: A method, information processing system, and computer program product manage computer executable instructions. At least one machine instruction for execution is received. The at least one machine instruction is analyzed. The machine instruction is identified as a predefined instruction for storing a variable length first operand in a memory location. Responsive to this identification and based on fields of the machine instruction, a relative location of a variable length second operand of the instruction with location of the first operand is determined. Responsive to the relative location having the predefined relationship, a first cracking operation is performed. The first cracking operation cracks the instruction into a first set of micro-ops (Uops) to be executed in parallel. The first set of Uops is for storing a first plurality of first blocks in the first operand. Each of said first block to be stored are identical. The first set Uops are executed.

Abstract: Fetching a cache line into a plurality of caches of a multilevel cache system. The multilevel cache system includes at least a first cache, a second cache on a next higher level and a memory, the first cache being arranged to hold a subset of information of the second cache, the second cache being arranged to hold a subset of information of a next higher level cache or memory if no higher level cache exists. A fetch request is sent from one cache to the next cache in the multilevel cache system. The cache line is fetched in a particular state into one of the caches, and in another state into at least one of the other caches.

Abstract: Processing of transactions within a computing environment is facilitated by taking actions to increase the chances of successfully executing a transaction. A counter is maintained that provides a count of how often a transaction has aborted. The counter increments the count each time the transaction is aborted, and it is reset to zero upon successful completion of the transaction or an interruption leading to no more re-executions of the transaction. If the count reaches a threshold value, then an interrupt is presented and transaction execution is unsuccessful. However, before the count reaches the threshold, a number of actions may be taken to increase the chances of successfully executing the transaction. These actions include actions to be performed within the processor executing the transaction, and/or actions to be performed against conflicting processors.

Abstract: A technique is provided for monitoring a value without repeated storage access. A processing circuit processes an instruction of a program that specifies a memory address of a memory location to be monitored. The processing circuit configures a monitor station for monitoring the memory location. The memory location includes a state descriptor for the program. The processing circuit receives a cross-invalidate request from a memory controller. The cross-invalidate request indicates to the monitor station that content of the memory location has been changed by another processing circuit.

Abstract: Embodiments relate to a transactional read footprint after a cache line eviction. An aspect includes executing one or more read instructions in an active transaction. A cross invalidate (XI) request for a target cache line is received, and it is determined if the target cache line is part of a congruence class in a local cache. It is further determined whether an extension flag associated with the congruence class is set. The extension flag is used to indicate that cache lines of the congruence class associated with the active transaction have been replaced based only on being least recently used and that the target cache line is not in the cache. Execution of the active transaction continues based on determining that the extension flag is not set. Execution of the active transaction is aborted based on determining that the extension flag is set.

Abstract: Embodiments relate to tracking a transactional execution footprint. An aspect includes receiving a store instruction which includes store data. It is determined if the store instruction is executing within a transaction that effectively delays committing stores to a shared cache until the transaction has completed. The store data is stored to a cache line in a local cache. The cache line is marked as dirty if the transaction is active. The stored data that was marked as dirty in the local cache is invalidated if the transaction has terminated abnormally. The stored data is un-marked if it is determined that the transaction has successfully ended.

Abstract: Embodiments relate to prefetch address translation in a computer processor. An aspect includes issuing, by prefetch logic, a prefetch request comprising a virtual page address. Another aspect includes, based on the prefetch request missing the TLB and the address translation logic of the processor being busy performing a current translation request, comparing a page of the prefetch request to a page of the current translation request. Yet another aspect includes, based on the page of the prefetch request matching the page of the current translation request, storing the prefetch request in a prefetch buffer.

Abstract: According to an embodiment, a computer system for cache management includes a processor and a cache, the computer system configured to perform a method including receiving a first store request for a first address in the cache and receiving a first fetch request for the first address in the cache. The method also includes executing the first store request and the first fetch request, latching the first store request in a store write-back pipeline in the cache, detecting, in the processor, a conflict following execution of the first store request and the first fetch request and receiving the first store request from a recycle path including the store write-back pipeline and executing the first store request a second time.

Abstract: Embodiments relate to controlling observability of transactional and non-transactional stores. An aspect includes receiving one or more store instructions. The one or more store instructions are initiated within an active transaction and include store data. The active transaction effectively delays committing stores to memory until successful completion of the active transaction. The store data is stored in a local storage buffer causing alterations to the local storage buffer from a first state to a second state. A signal is received that the active transaction has terminated. If the active transaction has terminated abnormally then: the local storage buffer is reverted back to the first state if the store data was stored by a transactional store instruction, and is propagated to a shared cache if the store instruction is non-transactional.

Abstract: A computer program product for mitigating conflicts for shared cache lines between an owning core currently owning a cache line and a requestor core. The computer program product includes a tangible storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method. The method includes determining whether the owning core is operating in a transactional or non-transactional mode and setting a hardware-based reject threshold at a first or second value with the owning core determined to be operating in the transactional or non-transactional mode, respectively. The method further includes taking first or second actions to encourage cache line sharing between the owning core and the requestor core in response to a number of rejections of requests by the requestor core reaching the reject threshold set at the first or second value, respectively.

Abstract: Embodiments relate to controlling observability of transactional and non-transactional stores. An aspect includes receiving one or more store instructions. The one or more store instructions are initiated within an active transaction and include store data. The active transaction effectively delays committing stores to memory until successful completion of the active transaction. The store data is stored in a local storage buffer causing alterations to the local storage buffer from a first state to a second state. A signal is received that the active transaction has terminated. If the active transaction has terminated abnormally then: the local storage buffer is reverted back to the first state if the store data was stored by a transactional store instruction, and is propagated to a shared cache if the store instruction is non-transactional.

Abstract: Embodiments relate to collision-based alternate hashing. An aspect includes receiving an incoming instruction address. Another aspect includes determining whether an entry for the incoming instruction address exists in a history table based on a hash of the incoming instruction address. Another aspect includes based on determining that the entry for the incoming instruction address exists in the history table, determining whether the incoming instruction address matches an address tag in the determined entry. Another aspect includes based on determining that the incoming instruction address does not match the address tag in the determined entry, determining whether a collision exists for the incoming instruction address. Another aspect includes based on determining that the collision exists for the incoming instruction address, activating alternate hashing for the incoming instruction address using an alternate hash buffer.

Abstract: Embodiments relate to determining the logical address of a transaction abort. In an embodiment, one or more instructions are received are received from an application. The one or more instructions are executed within a first transaction. The first transaction delays committing stores to memory until it has completed. At least one of the one or more instructions includes a first logical memory address. The first logical memory address corresponds to a first memory address in a memory system. It is determined if the first memory address is equal to a second memory address that is stored in a conflict register. Based on determining that they are equal the first logical memory address is saved as a logical address associated with a cross invalidate (XI) signal at a location available to the application.

Abstract: A technique is provided for monitoring a value without repeated storage access. A processing circuit processes an instruction of a program that specifies a memory address of a memory location to be monitored. The processing circuit configures a monitor station for monitoring the memory location. The memory location includes a state descriptor for the program. The processing circuit receives a cross-invalidate request from a memory controller. The cross-invalidate request indicates to the monitor station that content of the memory location has been changed by another processing circuit.

Abstract: A method and information processing system manage load and store operations that can be executed out-of-order. At least one of a load instruction and a store instruction is executed. A determination is made that an operand store compare hazard has been encountered. An entry within an operand store compare hazard prediction table is created based on the determination. The entry includes at least an instruction address of the instruction that has been executed and a hazard indicating flag associated with the instruction. The hazard indicating flag indicates that the instruction has encountered the operand store compare hazard. When a load instruction is associated with the hazard indicating flag, the load instruction becomes dependent upon all store instructions associated with a substantially similar hazard indicating flag.